Heavy hydrogen find alters origin of galaxy theory

A heavy form of hydrogen created just moments after the Big Bang has been found in larger quantities than expected in the Milky Way.

A heavy form of hydrogen created just moments after the Big Bang has been found in larger quantities than expected in the Milky Way. The finding could radically alter theories about star and galaxy formation, researchers said on Monday.

This form of hydrogen, called deuterium, has apparently been hiding out in interstellar dust grains, changing from an easily detectable gaseous form to a harder-to-see solid form, the French and US team of astrophysicists said.

Writing in the August 20 issue of the Astrophysical Journal, the researchers said they used NASA's Far Ultraviolet Spectroscopic Explorer, or FUSE satellite, to ferret out the hidden hydrogen.

Deuterium — a form of hydrogen with not only a proton but also a neutron in its nucleus — produces a tell-tale spectral fingerprint in the ultraviolet light range, which FUSE can see. Jeffrey Linsky of the University of Colorado, who led the study, said scientists had assumed that at least a third of the primordial deuterium present in the Milky Way was destroyed over time as it cycled through the stars.

But FUSE found deuterium exists in amounts less than 15 per cent below what was there originally. And it is not distributed evenly. So something in the theory is wrong, Linsky said.

“This implies that either significantly less material has been converted to helium and heavier elements in stars or that much more primordial gas has rained down onto the galaxy over its lifetime than had been thought,” he said. "